1. Field of the Invention
The present invention relates to endoscopes and more specifically to endoscopes and endoscope devices which are characterized by the orientation of plural images to their forceps opening when observing an object with plural images.
2. Description of the Related Art
Recently, a technology is known that autofluorescence from organisms or fluorescence of drugs which are injected into organisms is detected by, for example, an endoscope or the like as two-dimensional images. Diagnostic analysis can be performed on degeneration of vital tissues and disease conditions (for example, types of the diseases and the infiltrated areas) of cancers or the like.
When a light is illuminated onto a vital tissue, a fluorescence with a longer wavelength than that of the excitation light is generated. As fluorescent substances existing in organisms, for example, NADH (nicotineamide adenine dinucleotide), FMN (Flavin mononucleotide), pyridine nucleotide and the like can be mentioned. Recently, the interrelationship between such biological, endogenous substances and diseases has been increasingly made clear. In addition, since HpD (hematoporphyrin), Photofrin, and ALA (.delta.-amino levulinic acid) show clustering activities towards cancers, by injecting the substance into an organism and then observing the fluorescence of the substance, the disease area can be diagnosed.
Because such a fluorescence is extremely subtle, an extremely high-sensitive projection is essential for the observation. A device to conduct this high-sensitive projection is described, for example, in Japanese Unexamined Patent Publication No. 8-252218. Fluorescent observation endoscope devices possess a fluorescent observation endoscope having CCDs which are provided with an imaging element to image under a white illumination and image intensifiers, such as super high-sensitive imaging elements to image subtle autofluorescence which emits from an observation object under an illumination of a light with a band from ultra-violet to blue.
In accordance with such fluorescent observation endoscopes, regular observation under a white light and autofluorescent observation can be conducted selectively or consecutively, and much more information on the observation object can be offered to examiners compared to the conventional endoscope devices.
In general, is provided for an endoscope, a forceps channel in introducing treatment tools such as a forceps and the like to the tip of the endoscope so that biopsy or excision of lesion parts within an observation object can be conducted under the endoscopic observation.
In terms of the conventional fluorescent observation endoscopes, however, no description has made on positional relationship among an objective window for white light regular observation use, an objective window for fluorescent observation use, both of which exist at the tip part of the endoscope, and a forceps hole.
For example, in a conventional fluorescent observation endoscope, as shown in FIG. 10, when an object window for regular observation use 201 and an object window for fluorescent observation use 202 are disposed to be in the upper and lower position, respectively, at the tip plane of the endoscope in the figure, illumination windows 203a and 203b are individually provided near the object window for regular observation use 201 and the object window for fluorescent observation use 202, respectively. Further, a forceps hole 204 which is an opening part at the tip side of a forceps channel is disposed between the object window for regular observation use 201 and the illumination window 203a, A nozzle 205 for washing the object window for regular observation use 201 and the object window for fluorescent observation use 202 is disposed almost in the middle, as shown in FIG. 11 and FIG. 12. In a white observation image (FIG. 11), the forceps 206 appears the lower left on the monitor screen, while in a fluorescent observation image (FIG. 12), the forceps 206 appears from the upper left on the monitor screen.
In other words, because in some cases, in both of the regular observation images and the fluorescent observation images, treatments are conducted by the forceps 206 and the like, when the position of the forceps 206 on the monitor screen is different between the regular observation images and for the fluorescent observation images, a problem occurs that this situation throws operators into confusion.
In addition, endoscopes which are used for diagnosis based on regular observation images and fluorescent observation images are formed to selectively conduct the regular observation under a white light illumination and the fluorescent observation, to observe fluorescence which is emitted from a vital tissue under an illumination of an ultraviolet-to-blue light, by means of imaging means which are installed in or connected to the endoscope. Plural examples for these endoscopes are described in Japanese Unexamined Patent Application 8-252218.
The first example has a construction where two kinds of image-formation optical systems each for the regular observation use and for fluorescent observation use are disposed in parallel. Two kinds of solid imaging elements to convert the images from these image-formation optical systems into electric signals are provided at the tip or in the operation part of the endoscope. Under illumination by a white light and an excitation light which are transferred from a light source device in a time shared way, the imaging signals which are outputted from the individual solid imaging elements are selected for conditioning and designation in accordance with the timing controls on the illumination lights.
In the second example, an object optical system which is common to the regular observation and the fluorescent observation and a beam splitter which divides the regular observation image and the fluorescent observation image which are both emitted from the object optical system into two directions based on their wavelengths are provided at the tip part of an endoscope. Solid imaging elements which individually image the regular observation image and the fluorescent observation image which have been separated by the beam splitter are installed at the tip part or in the operation part of the endoscope.
But, because in the first endoscope device of Japanese Unexamined Patent Application 8-252218, the object optical system for regular observation use and the object optical system for fluorescent observation use are provided at the tip part of the endoscope in parallel, the field of visions differ between the processes of the regular observation and the fluorescent observation. Therefore, by switching the regular observation image to the fluorescent observation image and vice versa, the field of vision of these images, which are designated on the monitor, differ each other, resulting in the problem that operators experience confusion.
Also, with the second endoscope device of Japanese Unexamined Patent Application 8-252218, due to the reflex action of the beam splitter, the regular observation image and the fluorescent observation image have a mirroring relationship, so that a special signal conditioning to reverse one of the images needs to be essential.